1. Field of the Invention
The present invention relates to a zoom lens for a compact camera having a shorter back focal length.
2. Description of the Related Art
There has been an increasing demand for higher magnification and miniaturization of zoom lenses for compact cameras in recent years. Zoom lenses employed in compact cameras differ to those of single lens reflex (SLR) cameras, because in the compact cameras a longer back focal length is not required. Therefore, as an example of possible optical system, the so-called two-lens-group optical system, which only includes a first lens group of positive power and a second lens group of negative power in that order from the object side, can be employed in compact cameras. Accordingly, a simple structure and miniaturization of the zoom lenses having a reduced number of lenses can be attained.
However, in the above-described two lens-group zoom lens and under the condition that the number of lens elements is 4 or 5, if a zoom ratio of 2.5 or more is required, chromatic aberration, the travelling distance of the lens groups and entire length of the lens system are inevitably increased.